A security administrator is reviewing the system logs of a recently compromised server. They notice several log entries with failed login attempts followed by a single successful login attempt from an unfamiliar remote IP address. After the successful login, there are commands executed that elevate the privileges of the newly logged-in user. Which of the following actions should the security administrator prioritize to mitigate the immediate threat?
Conduct an immediate forensic analysis on the server.
Change the passwords for all user accounts.
Review and update firewall settings to restrict remote access.
Disable the compromised user account.